1636561 has 2 divisors, whose sum is σ = 1636562. Its totient is φ = 1636560.

The previous prime is 1636553. The next prime is 1636571. The reversal of 1636561 is 1656361.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1252161 + 384400 = 1119^2 + 620^2 .

It is a cyclic number.

It is not a de Polignac number, because 1636561 - 2³ = 1636553 is a prime.

It is a Chen prime.

It is an alternating number because its digits alternate between odd and even.

It is not a weakly prime, because it can be changed into another prime (1636501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 818280 + 818281.

It is an arithmetic number, because the mean of its divisors is an integer number (818281).

2^1636561 is an apocalyptic number.

It is an amenable number.

1636561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1636561 is an equidigital number, since it uses as much as digits as its factorization.

1636561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3240, while the sum is 28.

The square root of 1636561 is about 1279.2814389336. The cubic root of 1636561 is about 117.8448838008.

It can be divided in two parts, 1636 and 561, that added together give a cube (2197 = 13³).

The spelling of 1636561 in words is "one million, six hundred thirty-six thousand, five hundred sixty-one".